The present invention relates to the field of power electronics. It relates to a power semiconductor arrangement which comprises a multiplicity of power semiconductor switching elements of the same type, preferably configured identically, arranged in a plane, or particularly in a row, and to be connected in parallel. A load current terminal for the load current input and a load current terminal for the load current output are provided per switching element. For rapid low-loss switching of currents, power transistors, in particular insulated gate bipolar transistors (IGBTs) are often used in power, conversion and transmission technology. In order to be able to switch heavy currents (in particular of the order of 1 kA or more), a multiplicity of individual power semiconductor switching elements, also referred to below as power transistors, are in this case electrically connected in parallel. The power transistors are in this case often combined in modules, which inter alia permits simplified handling during installation and replacement, allows defined and optimized cooling, satisfies a range of safety aspects, etc. Inside a module, component groups or submodules are in this case often formed from subsets of the multiplicity of power transistors.
In terms of the switching behavior of the power semiconductor arrangement, it is generally desirable that a current can be switched on or off as rapidly as possible. Particularly in the case of voltage-controlled power transistors, in which a current can be switched between a first power electrode and a second power electrode by means of a control voltage applied between the first power electrode and a control electrode, this is made difficult inter alia by inductive effects. These inductive effects not only affect the control voltage and cause a deviation of the effective control voltage from the specified control voltage, but also affect the load current output and load current input.
For instance, an inductive influence furthermore takes place as a result of time-varying currents in the rest of the power transistors because of so-called mutual inductances, In current-carrying conductors, i.e. also around the load current terminals, magnetic fields are formed. The electrical current flowing in the terminals leads to the formation of a magnetic flux. The way in which these magnetic fields propagate in the space around the current-carrying conductors, and how large the magnetic flux resulting therefrom is, depends on the magnetic properties of the surroundings. In this case, not only the magnetic properties of the materials in the surroundings but also the presence of further magnetic fields, caused by other load current terminals, play a crucial role. By connection of at least two power semiconductor switching elements in parallel, a magnetic influence of the individual load current-carrying paths takes place in such a way that their inductances can vary greatly. This leads to an asymmetrical current distribution above all during the switching instant, so that the switching behavior of the overall power semiconductor arrangement is influenced thereby.
It has been found that the effect caused by the mutual inductance in power semiconductor arrangements consisting of a plurality of power semiconductor switching elements can be kept as small as possible when the load current terminals for the load current input and those for the load current output are arranged geometrically as close as possible next to one another, so that their magnetic fields can influence one another in a way which reduces the inductance. This is readily possible inside such an arrangement, but outer load current terminals, to which it is not possible to assign a load current terminal of opposite current direction so as to have an inductance-reducing effect, still always remain because of the geometrical arrangement. Overall, in the arrangement of a plurality of power semiconductor switching elements, the problem remains that the magnetic field set up enclosing the outer load current terminals in relation to the geometrical midpoint of the arrangement, or outer pairs thereof, differs from the magnetic field enclosing the inner load current terminals in relation to the geometrical midpoint of the arrangement, or inner pairs thereof, and therefore switching behavior of the outer power semiconductor switching elements undesirably turns out to be different than that of the inner power semiconductor switching elements because of this nonuniformity, in particular asymmetry.